Figure one.

Pathways by which luteinizing hormone action on the somatic cells of the ovarian follicle might lead to decreased cAMP in the oocyte, thus initiating the prophase-to-metaphase transition. This paper tests the hypothesis that LH signaling could inhibit cAMP production in the oocyte by inhibiting the receptor-G_s-adenylyl cyclase system in the oocyte (GPR3-G_s-AC3). Alternatively, LH signaling could stimulate cAMP degradation by stimulating cAMP phosphodiesterase (PDE3A), or could modulate transport of cAMP between the cumulus cells and oocyte through gap junctions, which are comprised at least mostly of connexin 37 subunits (GJA4) (Simon et al., 1997; Kidder and Mhawi, 2002; Veitch et al., 2004).